From: sto.mar@...
Date: 2013-07-10T14:14:46+09:00
Subject: Re: create variables depending on counter

Am 10.07.2013 00:03, schrieb stefan heinrich:
> can u say how I have to use the Hash with the headers. I have tried
> everything but it doesn't work.

That's not a very useful information...


You can take my first example:

Am 09.07.2013 17:47, schrieb sto.mar@web.de:
>> array = ['Car', 'Dog', 'Dog', 'Car', 'Dog']
>> indices = Hash.new {|h,k| h[k] = [] }
>> array.each_with_index {|element, index| indices[element] << index }
>> indices
>>    # => {"Car"=>[0, 3], "Dog"=>[1, 2, 4]}
>> indices['Car']
>>    # => [0, 3]
>> indices['Dog']
>>    # => [1, 2, 4]

assuming your data is given as a 2-dimensional array:

data = [
   ['Dog', 12],
   ['Car', 14],
   ['Car', 67],
   ['Dog', 98],
   ['Dog', 32]
]

then this would work (first, I create a hash with [] as the
default value, that's the trickiest part of the whole thing):

values = Hash.new {|h,k| h[k] = [] }
data.each {|header, value| values[header] << value }
p values['Dog']  # [12, 98, 32]
p values['Car']  # [14, 67]

Depending on how your data is given, you need to modify
the second line.

I suggest you also look into the docs for the Hash class and
make heavy use of irb.

Regards,
Marcus


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